Method and apparatus of flexible data transmissions and receptions in next generation cellular networks

ABSTRACT

A communication method and system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for Internet of Things (IoT) is provided. The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The method for obtaining numerology information by a user equipment (UE) includes detecting synchronization signals, obtaining first numerology information for the synchronization signals, decoding a physical broadcast channel (PBCH) based on the first numerology information, obtaining second numerology information for a physical downlink control channel (PDCCH) according to a result of the decoding, and receiving control information on the PDCCH based on the second numerology information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 16/695,966, filed on Nov. 26, 2019, which is a continuationapplication of prior application Ser. No. 15/801,897, filed on Nov. 2,2017, which has issued as U.S. Pat. No. 10,499,371 on Dec. 3, 2019 whichis based on and claims the benefit under 35 U.S.C. § 119(e) of a U.S.Provisional application filed on Nov. 3, 2016 in the U.S. Patent andTrademark Office and assigned Ser. No. 62/416,941, and U.S. Provisionalapplication filed on Jan. 6, 2017 in the U.S. Patent and TrademarkOffice and assigned Ser. No. 62/443,278, the entire disclosure of eachwhich is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system. Moreparticularly, the present disclosure relates to an apparatus and methodfor providing flexible data transmissions and receptions in a wirelesscommunication system.

BACKGROUND

To meet the demand for wireless data traffic having increased sincedeployment of fourth generation (4G) communication systems, efforts havebeen made to develop an improved fifth generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘Beyond 4G Network’ or a ‘Post long term evolution(LTE) System’. The 5G communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), full dimensional MIMO(FD-MIMO), array antenna, an analog beam forming, large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) andsliding window superposition coding (SWSC) as an advanced codingmodulation (ACM), and filter bank multi carrier (FBMC), non-orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA) as anadvanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof Things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofEverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “Security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing information technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, MTC, and M2M communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RAN as theabove-described Big Data processing technology may also be considered tobe an example of convergence between the 5G technology and the IoTtechnology.

In recent years, several broadband wireless technologies have beendeveloped to meet the growing number of broadband subscribers and toprovide more and better applications and services. The second generation(2G) wireless communication system has been developed to provide voiceservices while ensuring the mobility of users. The third generation (3G)wireless communication system supports not only the voice service butalso data service. The 4G wireless communication system has beendeveloped to provide high-speed data service. However, the 4G wirelesscommunication system currently suffers from lack of resources to meetthe growing demand for high speed data services. Therefore, the 5Gwireless communication system is being developed to meet the growingdemand of various services with diverse requirements, e.g., high speeddata services, ultra-reliability and low latency applications andmassive machine type communication.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Due to the widely supported services and various performancerequirements, there is high potential that the user equipment (UE) mayhave different capabilities, e.g., in terms of supported UE bandwidth(BW). Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to address the need for flexible UE bandwidth support inthe design of 5G network, and the flexible network access for UEs withdifferent bandwidth capabilities.

In accordance with an aspect of the present disclosure, a method forobtaining numerology information by a UE is provided. The methodincludes detecting synchronization signals, obtaining first numerologyinformation for the synchronization signals, decoding a physicalbroadcast channel (PBCH) based on the first numerology information,obtaining second numerology information for a physical downlink controlchannel (PDCCH) according to a result of the decoding, and receivingcontrol information on the PDCCH based on the second numerologyinformation.

The second numerology information indicates a subcarrier spacing for thePDCCH within a subcarrier spacing set. Wherein the subcarrier spacingset is for lower frequency bands or higher frequency bands, the lowerfrequency bands are below reference frequency band and the higherfrequency bands are above the reference frequency band.

The method for the obtaining numerology information by the UE includesobtaining first information on bandwidth for PDCCH transmissionaccording to a result of the decoding.

The method for the obtaining numerology information by the UE includesobtaining second information according to a result of the decoding, thesecond information including at least one of a candidate physicalresource block (PRB) for PDCCH transmission and offset between a centerof the PDCCH transmission and a reference frequency.

The method for the obtaining numerology information by the UE includesobtaining third information on a start symbol index to monitor the PDCCHaccording to a result of the decoding.

In accordance with another aspect of the present disclosure, a methodfor providing numerology information by a base station in a wirelesscommunication system is provided. The method includes transmitting, to aUE, synchronization signals and first numerology information for thesynchronization signals, generating second numerology information for aPDCCH, transmitting, to the UE, the second numerology information on aPBCH based on the first numerology information, and transmitting, to theUE, control information on the PDCCH based on the second numerologyinformation.

The second numerology information indicates a subcarrier spacing for thePDCCH within a subcarrier spacing set. Wherein the subcarrier spacingset is for lower frequency bands or higher frequency bands, the lowerfrequency bands are below reference frequency band and the higherfrequency bands are above the reference frequency band.

The method for providing numerology information by a base stationincludes generating first information on bandwidth for PDCCHtransmission, and transmitting, to the UE, the first information.

The method for providing numerology information by a base stationincludes generating second information including at least one of acandidate PRB for PDCCH transmission and offset between a center of thePDCCH transmission and a reference frequency, and transmitting, to theUE, the second information.

The method for providing numerology information by a base stationincludes generating third information on a start symbol index to monitorthe PDCCH, and transmitting, to the UE, the third information.

In accordance with another aspect of the present disclosure, a UE forobtaining numerology information in a wireless communication system. TheUE includes a transceiver configured to transmit and receive a signal,and a controller coupled with the transceiver and configured to detectsynchronization signals, obtain first numerology information for thesynchronization signals, decode a PBCH based on the first numerologyinformation, obtain second numerology information for a PDCCH accordingto a result of the decoding, and receive control information on thePDCCH based on the second numerology information.

In accordance with another aspect of the present disclosure, there is abase station for providing numerology information in a wirelesscommunication system. The base station includes a transceiver configuredto transmit and receive a signal, and a controller coupled with thetransceiver and configured to transmit, to a UE, synchronization signalsand first numerology information for the synchronization signals,generate second numerology information for a PDCCH, transmit, to the UE,the second numerology information on a PBCH based on the firstnumerology information, and transmit, to the UE, control information onthe PDCCH based on the second numerology information.

According to the present disclosure, a method for providing flexibledata transmissions and receptions in a wireless communication system isprovided. The method provides the flexible network access for UEs withdifferent bandwidth capabilities

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates resources divided into transmission time intervals(TTIs) in time domain and resource blocks (RBs) in frequency domainaccording to an embodiment of the present disclosure;

FIG. 2 illustrates an example for transmission of synchronizationsignals and broadcast channel within a pre-defined bandwidth accordingto an embodiment of the present disclosure;

FIG. 3 illustrates an example for transmission of synchronizationsignals and broadcast channel within a pre-defined bandwidth accordingto an embodiment of the present disclosure;

FIG. 4 illustrates a resource grid in time and frequency domainaccording to an embodiment of the present disclosure;

FIG. 5 illustrates an RB grid defined according to embodiments of thepresent disclosure;

FIG. 6 illustrates a flowchart for determining an RB grid by a userequipment (UE) according to an embodiment of the present disclosure;

FIG. 7 illustrates a flowchart for determining an RB grid by a UE basedon configured numerology according to an embodiment of the presentdisclosure;

FIG. 8 illustrates a flowchart for mapping resources by a base stationaccording to an embodiment of the present disclosure;

FIG. 9 illustrates a flowchart for mapping resources by a UE accordingto an embodiment of the present disclosure;

FIG. 10 illustrates an example for UEs with different bandwidthcapabilities according to an embodiment of the present disclosure;

FIG. 11 illustrates an example for a control subband according to anembodiment of the present disclosure;

FIG. 12 illustrates an example for a control subband according toanother embodiment of the present disclosure;

FIG. 13A illustrates a flowchart for receiving physical downlink controlchannel (PDCCH) by a UE according to an embodiment of the presentdisclosure;

FIG. 13B illustrates a flowchart for transmitting PDCCH by a basestation according to an embodiment of the present disclosure;

FIG. 14 illustrates a flowchart for obtaining numerology information bya UE according to an embodiment of the present disclosure;

FIG. 15 illustrates a flowchart for obtaining numerology informationused for PDCCH by a UE according to embodiments of the presentdisclosure;

FIG. 16 illustrates an example for indicating location and size of thePDCCH according to an embodiment of the present disclosure;

FIG. 17 illustrates an example for indicating location and size of thePDCCH according to another embodiment of the present disclosure;

FIG. 18 illustrates an example for long term evolution-new radio(LTE-NR) coexistence in the same spectrum respectively for frequencydivision duplex (FDD) and time division duplex (TDD) modes according toan embodiment of the present disclosure;

FIG. 19 illustrates an example for a subframe boundary aligned betweenNR and LTE according to an embodiment of the present disclosure;

FIG. 20 illustrates an example for first two orthogonalfrequency-division multiplexing (OFDM) symbols reserved in amulticast-broadcast single-frequency network (MBSFN) subframe accordingto an embodiment of the present disclosure;

FIG. 21 illustrates an example for subcarrier spacing used in new radio(NR) according to an embodiment of the present disclosure;

FIG. 22 illustrates a flowchart for obtaining PDCCH location and sizeinformation by a UE according to an embodiment of the presentdisclosure;

FIG. 23 illustrates an example for a common control channel according toan embodiment of the present disclosure;

FIG. 24 illustrates an example for a control subband according to anembodiment of the present disclosure;

FIG. 25 illustrates an example for keeping the same radio frequency (RF)bandwidth for both control and data channels according to an embodimentof the present disclosure;

FIG. 26 illustrates a flowchart for indicating if there is any activedownlink control information (DCI) transmission in the current controlsubband according to an embodiment of the present disclosure;

FIG. 27 illustrates a flowchart for indicating the aggregation levels ofDCIs transmitted in the current TTI according to an embodiment of thepresent disclosure;

FIG. 28 illustrates a flowchart for indicating UE groups scheduled inthe current TTI according to an embodiment of the present disclosure;

FIG. 29 illustrates that control units (CUs) available for PDCCHtransmission are numbered from zero and upward according to anembodiment of the present disclosure;

FIG. 30 illustrates an aggregation of control channel elements (CCEs)according to an embodiment of the present disclosure;

FIG. 31 illustrates that CUs used for PDCCH transmission are locatedwithin the control subband according to an embodiment of the presentdisclosure;

FIG. 32 illustrates that the resource element groups (REGs) are indexedin the order of closest subcarrier index first, and then lowest symbolindex according to an embodiment of the present disclosure;

FIG. 33 illustrates a structure of a UE according to an embodiment ofthe present disclosure; and

FIG. 34 illustrates a structure of a base station according to anembodiment of the present disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose and not for the purposeof limiting the present disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

1) System Operation

FIG. 1 illustrates resources divided into transmission time intervals(TTIs) in time domain and resource blocks (RBs) in frequency domainaccording to an embodiment of the present disclosure.

Considering an orthogonal frequency-division multiplexing (OFDM) basedcommunication system, a resource element can be defined by a subcarrierduring on OFDM symbol duration. In the time domain, a TTI can be definedwhich is composed of multiple OFDM symbols. In the frequency domain, aRB can be defined which is composed of multiple OFDM subcarriers.

Referring to FIG. 1 , the resources can be divided into TTIs in timedomain and RBs in frequency domain. Typically, an RB can be a baselineresource unit for scheduling in the frequency domain, and a TTI can be abaseline resource unit for scheduling in the time domain. Depending ondifferent service features and system requirements, different TTIduration can be used.

FIG. 2 illustrates an example for transmission of synchronizationsignals and broadcast channel within a pre-defined bandwidth accordingto an embodiment of the present disclosure.

In the fourth generation (4G) long term evolution (LTE) networks,flexible system bandwidth is supported (e.g., 1.4 MHz/3 MHz/5 MHz/10MHz/15 MHz/20 MHz), and the channel designs are mostly based on theoperated system bandwidth. This gives mandatory requirement that the UEshould operate in the same bandwidth with the system, except in initialaccess when UE has no information of the system bandwidth. Since the UEshave no information of the system bandwidth in the initial access, theessential signals and channels are transmitted based on a pre-definedbandwidth, e.g., the minimum bandwidth supported by the networks.

Referring to FIG. 2 , the transmission of the synchronization signals(e.g., primary synchronization signal (PSS) and secondarysynchronization signal (SSS)) and broadcast channel (e.g., physicalbroadcast channel (PBCH)) is limited within a pre-defined bandwidth BW0in the center of the system bandwidth, which is accessible to all UEs.After receiving the PBCH, it is possible that the UEs obtain the systembandwidth, e.g., indicated in the master information block (MIB) carriedby PBCH. Then it is possible that the transmissions of otherchannels/signals occupy the full system bandwidth, because the UEs canaccess the actual system bandwidth after obtaining the system bandwidthinformation.

For the UEs with less bandwidth than the system bandwidth, it isimpossible for the UEs to access the channel which occupies full systembandwidth, e.g., enhanced machine type communication (eMTC) andnarrowband internet-of-things (NB-IoT). There is limitation of thecurrent systems to support flexible access for UEs with variousbandwidths.

In the future cellular networks, there is a need to multiplex differentservices, which may require different numerologies due to the variousperformance requirements. Assuming the LTE numerology as a baseline,e.g., subcarrier spacing of 15 kHz, the scaled LTE numerology can beconsidered to support diverse services, e.g., 30 kHz, 60 kHz, and so on.In addition, it is possible that the UEs may support flexible bandwidth.In the present disclosure, the methods of flexible control channeldesign are proposed for the future cellular networks, e.g., LTE-advanced(LTE-A) or fifth generation (5G).

FIG. 3 illustrates an example for transmission of synchronizationsignals and broadcast channel within a pre-defined bandwidth accordingto an embodiment of the present disclosure.

Considering that the UEs may have different bandwidth, the downlinksignals and channels need to be designed to support various UEs withflexible bandwidth. The essential signals and channels can be designedbased on a pre-defined bandwidth, e.g., the minimum bandwidth supportedby the UEs, or minimum bandwidth supported by the UEs targeted to acertain service.

Referring to FIG. 3 , the transmission of the synchronization signals(e.g., PSS and SSS) and broadcast channel (e.g., PBCH) is limited withina bandwidth BW0. Since the UEs have no information of the systembandwidth in the initial access, the UEs search the synchronizationsignals with the bandwidth BW0.

After synchronization is detected, the PBCH can be received in the samebandwidth BW0. After receiving the PBCH, it is possible that the UEsobtain the system bandwidth, e.g., indicated in the MIB carried by PBCH.The numerology used by the physical downlink control channel (PDCCH) maybe different from that for synchronization and PBCH transmission, therelated parameters (e.g., subcarrier spacing, CP pattern) can beindicated in the MIB.

In addition, since the UEs have different capabilities in terms ofsupported bandwidth, not all UEs can receive the signals in the fullsystem bandwidth. Depending on the bandwidth options supported by theUEs, the PDCCH may not occupy the full system bandwidth. Even though thePDCCH transmission occupies the whole system bandwidth, for the UEswhich have a bandwidth less than the system bandwidth, it is possible toallow the UEs to decode PDCCH within its supported bandwidth.

2) Resource Block (RB) Grid

FIG. 4 illustrates a resource grid in time and frequency domainaccording to an embodiment of the present disclosure.

Give a certain system bandwidth, there is a need to define the RB interms of time/frequency resources. Generally, given a transmissionbandwidth B_(TX), there are an integer number of subcarriers, e.g.,N_(sc) ^(Total). The number of available subcarriers may depend on thesubcarrier spacing Δf. It may be assumed that the system supportsmultiple subcarrier spacing values, e.g., Δf₀, Δf₁, Δf₂, Δf₃, . . . ,Δf_(N−1), the number of available subcarriers when using the subcarrierspacing Δf_(n) (0≤n<N−1) can be expressed by

$N_{sc}^{Total} = {\left\lfloor \frac{B_{TX}}{\Delta\; f_{n}} \right\rfloor.}$An RB is described by K subcarriers and L OFDM/SC-FDMA symbols.

Referring to FIG. 4 , an example of the resource grid is illustrated.The number of RBs N_(RB) depends on the transmission bandwidth and usedsubcarrier spacing Δf_(n) configured in the cell. In most cases thenumber of subcarriers per RB can be pre-defined, e.g., K=12. There arealso cases that the number of subcarriers can be less than K. The numberof OFDM/SC-FDMA symbols in a slot may depend on the cyclic prefix lengthconfigured in the system. Each element in the resource grid is called aresource element and is uniquely defined by the index pair (k, l) in aslot where k=0, . . . N_(sc) ^(Total)−1 and l=0, . . . , L−1 are theindices in the frequency and time domains, respectively.

FIG. 5 illustrates an RB grid defined according to embodiments of thepresent disclosure.

Several ways can be considered to define the RB grid.

Option 1: The RB grid is defined from one side of the system bandwidth.That means the RB boundary is always aligned with the edge of one sidein the system bandwidth. The system bandwidth here may also mean theactual transmission bandwidth, assuming some guardband is used in theedge of the system bandwidth.

Without loss of generality, the RB can be mapped from the lowerfrequency side. This means the RB boundary is aligned with the lowerfrequency side.

Referring to FIG. 5 , the first RB is composed of the subcarriers 0 toK−1, and the second RB is composed of the subcarriers K to 2K−1, and soforth. Thus, there are at least

$M = \left\lfloor \frac{N_{sc}^{Total}}{K} \right\rfloor$RBs with size of K subcarrier. It is possible that there may be a numberof subcarriers remained in the edge side, i.e., K₁=N_(sc)^(Total)=mod(N_(sc) ^(Total),K). If K₁=0, the system bandwidth fits withan integer number (i.e., M) of RBs with size of K subcarriers. If K₁>0,there can be different approaches to handle the remaining K₁subcarriers:

Option 1-1: The remaining K₁ subcarriers are always counted as one RB,which means there are total M+1 RBs in the system bandwidth. There are MRBs with size of K subcarriers, and 1 RB with size of K₁ subcarriers.

Option 1-2: The remaining K₁ subcarriers are always discarded and notcounted as one RB, which means there are total M RBs in the systembandwidth, with size of K subcarriers.

Option 1-3: For different numerology case, whether to count theremaining K₁ subcarriers as one RB can be different. For differentnumerology cases, the RB size is different from each other. For example,the RB size with 12 subcarriers are 180 kHz, 360 kHz, 720 kHz, 1440 kHz,respectively for the subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, 120kHz. With different amount of resources per RB for differentnumerologies, different operation can be used for different numerologycases. For example, when the subcarrier spacing is larger than apredefined value, i.e., larger RB size case, Option 1-1 is used.Otherwise for smaller subcarrier spacing, i.e., smaller RB size case,Option 1-2 is used.

Option 1-4: There can be an indication signaled in the systeminformation, to inform UEs if to count the remaining K₁ subcarriers (ifany) as one RB or not, i.e., Option 1-1 or Option 1-2. Based on theindication, the UE can determine the RB grid mapping for the remainingless than K subcarrier if any. Similarly, the indication can be appliedto all numerology cases. It is also possible to have numerology specificindication. It is also possible to indicate a certain numerology(subcarrier spacing) value, the operation can be different for the casethat subcarrier spacing larger than the indicated value, and the casethat subcarrier spacing smaller than the indicated value. For example,when the subcarrier spacing is larger than the indicated value (largerRB size), Option 1-1 is used. Otherwise, for smaller subcarrier spacing(smaller RB size), Option 1-2 is used.

Option 1-5: There can be a pre-defined condition or rule to determine ifthe remaining K₁ subcarriers can be counted as one RB. For example, ifKlis larger than or equal to a pre-defined threshold Y

$\left( {{e.g.},{Y = \frac{K}{2}}} \right),$the remaining K₁ subcarriers are counted as one RB. Otherwise, they arediscarded and not counted as one RB. In case that K₁ is larger than orequal to a pre-defined threshold Y, it is also possible that only thefirst Y subcarriers are counted as one RB and remaining K₁−Y subcarriersare not used or counted, rather than make an RB with arbitrary number ofsubcarriers. This ensures that the smaller RB in the edge side (ifpresent) always has a fixed size (i.e., Y subcarriers) for a givennumerology. The pre-defined threshold can be the same for all numerologycases. Alternatively, the pre-defined threshold can be different fordifferent numerology cases.

Option 1-6: The basic operation is similar as that in Option 1-5, i.e.,but the threshold Y can be configured in the system, e.g., signaled inthe system information. Based on the configured value, the UE candetermine the RB grid mapping for the remaining less than K subcarrierif any. Similarly, the range of the threshold configurations can bedifferent for different numerology cases.

Option 2: The RB grid is defined from the center of the systembandwidth. That means the RB boundary is always aligned with the centerin the system bandwidth. The system bandwidth here may also mean theactual transmission bandwidth, assuming some guardband is used in theedge of the system bandwidth.

The RB can be mapped from the center of the system bandwidth. This meansthe RB boundary is aligned with the center of the system bandwidth. Forexample, in the lower frequency side half system bandwidth, there aresubcarriers 0 to

$\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor - 1.$

In the higher frequency side half system bandwidth, there aresubcarriers

$\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor$to N_(sc) ^(Total)−1. The RBs are counted from the center to both sides.As shown in FIG. 2B, in the higher frequency side half system bandwidth,one RB is composed of the subcarriers

${{\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor\mspace{14mu}{to}\mspace{14mu}\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor} + K - 1},$and the next RB is composed of the subcarriers

${\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor\; + {K\mspace{11mu}{to}\mspace{14mu}\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor} + {2K} - 1},$and so forth. Similarly, in the lower frequency side half systembandwidth, one RB is composed of the subcarriers

${\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor - {K\mspace{14mu}{to}\mspace{14mu}\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor} - 1},$and the next RB is composed of the subcarriers

${\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor - {2K\mspace{14mu}{to}\mspace{14mu}\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor} - K - 1},$and so forth. Thus, there are at least

$M = {2\left\lfloor \frac{N_{sc}^{Total}}{2K} \right\rfloor}$RBs with size of K subcarrier. It is possible that there may be a numberof subcarriers remained in the edge of both sides, i.e.,

$K_{2} = {{{mod}\left( \ {\left\lfloor \frac{N_{sc}^{Total}}{2} \right\rfloor,K} \right)}.}$If K₂=0, the system bandwidth is fit with an integer number (i.e., M) ofRBs with size of K subcarriers. If K₂>0, there can be differentapproaches to handle the remaining K₂ subcarriers:

Option 2-1: In both edge sides, the remaining K₂ subcarriers are alwayscounted as one RB, which means there are total M+2 RBs in the systembandwidth. There are M RBs with size of K subcarriers, and 2 RBs withsize of K₂ subcarriers.

Option 2-2: In both edge sides, the remaining K₂ subcarriers are alwaysdiscarded and not counted as one RB, which means there are total M RBsin the system bandwidth, with size of K subcarriers.

Option 2-3: For different numerology case, whether to count theremaining K₂ subcarriers as one RB can be different. For differentnumerology cases, the RB size is different from each other. For example,the RB size with 12 subcarriers are 180 kHz, 360 kHz, 720 kHz, 1440 kHz,respectively for the subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, 120kHz. With different amount of resources per RB for differentnumerologies, different operation can be used for different numerologycases. For example, when the subcarrier spacing is larger than apredefined value, i.e., larger RB size case, Option 2-1 is used.Otherwise for smaller subcarrier spacing, i.e., smaller RB size case,Option 2-2 is used.

Option 2-4: There can be an indication signaled in the systeminformation, to inform UEs if to count the remaining K₂ subcarriers (ifany) as one RB or not, i.e., Option 2-1 or Option 2-2. Based on theindication, the UE can determine the RB grid mapping for the remainingless than K subcarrier if any. Similarly, the indication can be appliedto all numerology cases. It is also possible to have numerology specificindication. It is also possible to indicate a certain numerology(subcarrier spacing) value, the operation can be different for the casethat subcarrier spacing larger than the indicated value, and the casethat subcarrier spacing smaller than the indicated value. For example,when the subcarrier spacing is larger than the indicated value (largerRB size), Option 2-1 is used. Otherwise, for smaller subcarrier spacing(smaller RB size), Option 2-2 is used.

Option 2-5: There can be a pre-defined condition or rule to determine ifthe remaining K₂ subcarriers can be counted as one RB. For example, ifK₂ is larger than or equal to a pre-defined threshold Y

$\left( {{e.g.},\ {Y = \frac{K}{2}}} \right),$the remaining K₂ subcarriers are counted as one RB. Otherwise, they arediscarded and not counted as one RB. In case that K₂ is larger than orequal to a pre-defined threshold Y, it is also possible that only thefirst Y subcarriers are counted as one RB and remaining K_(2−Y)subcarriers are not used or counted, rather than make an RB witharbitrary number of subcarriers. This ensures that the smaller RB in theedge side (if present) always has a fixed size (i.e., Y subcarriers) fora given numerology. The pre-defined threshold can be the same for allnumerology cases. Alternatively, the pre-defined threshold can bedifferent for different numerology cases.

Option 2-6: The basic operation is similar as that in Option 2-5, i.e.,but the threshold Y can be configured in the system, e.g., signaled inthe system information. Based on the configured value, the UE candetermine the RB grid mapping for the remaining less than K subcarrierif any. Similarly, the range of the threshold configurations can bedifferent for different numerology cases.

FIG. 6 illustrates a flowchart for determining an RB grid by a UEaccording to an embodiment of the present disclosure.

Referring to FIG. 6 , the UE's behavior to determine the RB grid isillustrated, at the stage when the UE connects to the system. UEs firstdetect synchronization signals in operation S610, and then decode PBCHin operation S620. The numerology for monitoring PDCCH can be the sameas that of PBCH, or can be indicated in the MIB. Based on the numerologyand system bandwidth information signaled in the MIB, which is obtainedby the UE in operation S630, the UEs derive the RB grid structure basedon the pre-defined rule in operation S640. The next-generation Node B(gNB) can configure UE-specific numerology. After receiving theconfigured numerology, the UE needs to derive the RB grid based on theconfigured numerology.

FIG. 7 illustrates a flowchart for determining an RB grid by a UE basedon configured numerology according to an embodiment of the presentdisclosure.

Referring to FIG. 7 , the UE's behavior to determine the RB grid basedon configured numerology is illustrated. The UE receives the numerologyinformation (subcarrier spacing) from the system information or L1signaling in operation S710. The UE derives the RB grid based on thesubcarrier spacing and BW according to the predefined rule in operationS720.

FIG. 8 illustrates a flowchart for mapping resources by a base stationaccording to an embodiment of the present disclosure.

Referring to FIG. 8 , the gNB (or base station) decides the RBs used fortransmission (control or data) in operation S810. The gNB checks ifthere are fractional RBs included for transmission in operation S820. Ifthere are fractional RBs included for transmission, the gNB calculatesthe number of available REs considering the fractional RBs based on thepre-defined rule for fractional RB case in operation S830. If there arenot fractional RBs included for transmission, the gNB calculates thenumber of available REs based on the default rule (normal RBs case) inoperation S840. The gNB performs proper resource mapping based on thetotal amount of available REs in operation S850.

FIG. 9 illustrates a flowchart for mapping resources by a UE accordingto an embodiment of the present disclosure.

Referring to FIG. 9 , the UE decides the allocated RBs for reception(control or data) in operation S910. The UE checks if there arefractional RBs included for reception in operation S920. If there arefractional RBs included for reception, the UE calculates the number ofavailable REs considering the fractional RBs based on the pre-definedrule for fractional RB case in operation S930. If there are notfractional RBs included for reception, the UE calculates the number ofavailable REs based on the default rule (normal RBs case) in operationS940. The UE performs proper resource mapping based on the total amountof available REs in operation S950.

If the fractional RBs (RB with a size less than the full size RB) existin the edge side of a given system bandwidth under a certain numerology,the gNB needs to consider the actual number of available REs when thefractional RBs are used for control channel or data channeltransmission. In FIG. 8 and FIG. 9 , the gNB's and UE's behaviors areillustrated respectively.

3) Physical Downlink Control Channel (PDCCH) Design

FIG. 10 illustrates an example for UEs with different bandwidthcapabilities according to an embodiment of the present disclosure.

Given a PDCCH transmission BW, it is possible that the UEs withdifferent BW can decode the PDCCH by receiving a portion of PDCCH, e.g.,a portion corresponding to the UE's BW.

Referring to FIG. 10 , assuming that the control channel (PDCCH) istransmitted in the full BW, the UEs which have a BW less than the fullBW, e.g., BW1, BW2, can decode the PDCCH by receiving the PDCCH portionwithin BW1 or BW2. The PDCCH may occupy one or multiple OFDM symbols,e.g., 1, 2, or 3.

The PDCCH may include multiple control subbands in the frequency domain.The size of a subband may depend on several parameters, e.g., theminimum UE BW, the system bandwidth case, the reference numerology usedin the cell, and the frequency band case. It is possible that there aredifferent subband sizes in the same cell.

To support different UE BW cases, there can be a common control subbandwhich is accessible to all the UEs before connection to the network. Thesize of the common control subband may depend on the minimum UE BW, thesystem bandwidth, the reference numerology used in the cell, and thefrequency band case. The common control subband may convey the essentialsystem information, the control channel parameters, and controlinformation of system information, paging, and random access. The commoncontrol subband can be the default control channel for UEs in idle modeto monitor the control channel. After the UE is connected to the system,the gNB can configure a UE-specific control subband to UE for PDCCHmonitoring.

FIG. 11 illustrates an example for a control subband according to anembodiment of the present disclosure.

Referring to FIG. 11 , a control subband may include the common controlsubband. If configured, the UE may monitor the configured controlsubband including the common control subband as well. It is alsopossible that a control subband does not overlap with the common controlsubband.

FIG. 12 illustrates an example for a control subband according toanother embodiment of the present disclosure.

Referring to FIG. 12 , the configured control subband may occupy anumber of contiguous physical resource blocks (PRBs) in the frequencydomain and not overlap with the common control subband. If configured,the UE may only monitor the configured control subband.

In FIG. 13A and FIG. 13B, a flowchart of UE behavior to receive PDCCHand gNB behavior to transmit PDCCH is illustrated.

FIG. 13A illustrates a flowchart for receiving PDCCH by a UE accordingto an embodiment of the present disclosure.

Referring to FIG. 13A, a UE detects PSS/SSS/PBCH and obtains theparameters (e.g., numerology/BW/location) used for PDCCH transmission inoperation S1310. The UE receives PDCCH in a common control sub-band, andobtains system information in operation S1320. The UE accesses thesystem and sends UE capability information (e.g., UE BW information) tothe gNB in operation S1330. The UE receives the information of theconfigured control sub-band monitoring from gNB in operation S1340. TheUE receives PDCCH within the configured control sub-band in operationS1350. The UE detects its PDCCH(s) in the configured control sub-band inoperation S1360.

FIG. 13B illustrates a flowchart for transmitting PDCCH by a basestation according to an embodiment of the present disclosure.

Referring to FIG. 13B, a gNB (or a base station) receives random accessfrom a UE in operation S1360. The gNB sends random access response to UEin a common control sub-band in operation S1370. The gNB receives UEcapability information (e.g., UE BW information) in operation S1375. ThegNB configures the control sub-band for PDCCH monitoring to UE inoperation S1380. The gNB maps PDCCH in the control sub-band configuredto UE in operation S1385. The gNB sends PDCCH to the UE in operationS1390.

4) Physical Downlink Control Channel (PDCCH) Numerology Indication

It may be assumed that the system supports multiple subcarrier spacingvalues, e.g., Δf₀, Δf₁, Δf₂, Δf₃, . . . , Δf_(N−1) (whereΔf_(n)<Δf_(n+1), 0≤n<N−1); the usage of certain subcarrier spacing maydepend on the service and system requirement. To reduce the complexityin the initial access, the subcarrier spacing for synchronization andPBCH transmission can be pre-defined or selected by the gNB from thefull set or a subset of the supported subcarrier spacing values. Thesame subcarrier spacing can be used for synchronization and PBCHtransmission. However, the subcarrier spacing for PDCCH transmission canbe different from the one used for synchronization and PBCHtransmission. If there are multiple control subbands, the indication canbe at least applicable to a pre-defined common control subband.

The subcarrier spacing used for PDCCH or a common control subband can beindicated in the payload of PBCH, i.e., MIB. The following indicationmethods can be used:

Option 1:

Explicit indication of the PDCCH subcarrier spacing, e.g., ┌log₂N┐ bitscan be used to indicate which subcarrier spacing is used, among {Δf₀,Δf₁, Δf₂, Δf₃, . . . , Δ_(N−1)}.

Option 2:

Indicating the PDCCH subcarrier spacing among a pre-defined subcarrierspacing subset. For example, the full set of subcarrier spacing can bedivided into multiple subsets. An example of two subset can be {Δf₀,Δf₁, Δf₂, Δf₃, . . . , Δ_(N) ₁ ⁻¹}, {Δf_(N) ₁ , Δf_(N) ₁ ₊₁, Δf_(N) ₁₊₂, Δf_(N) ₁ ₊₃, . . . , Δf_(2N) ₁ ⁻¹}, which are respectively used forlower frequency bands (e.g., below-6 GHz frequency band) and higherfrequency bands (e.g., above-6 GHz frequency band). If the subcarrierspacing used by synchronization and PBCH belong to a subset, theindication only applies to the candidate subcarrier spacing in thecorresponding subset which includes in the subcarrier spacing used bysynchronization and PBCH. For example, if the subcarrier spacing used bysynchronization and PBCH is Δf₀, the indication bits can be used toindicate which subcarrier spacing is used, among the subset {Δf₀, Δf₁,Δf₂, Δf₃, . . . , Δ_(N) ₁ ⁻¹} which includes Δf₀.

Option 3: Indicating the relationship between the PDCCH subcarrierspacing and Sync/PBCH subcarrier spacing. It may be assumed that thesubcarrier spacing used by synchronization and Sync/PBCH is Δf_(n)(0≤n<N), several bits can be used to indicate the subcarrier spacingused for control channel (PDCCH) among a subset of the subcarrierspacing values closes to Δf_(n). Based on a pre-define rule, the subsetcan be constructed in different way. The subset can be comprised ofseveral subcarrier spacing values equal to and large than Δf_(n)supported in the system, e.g., {Δf_(n), Δf_(n+1), Δf_(n+2), Δf_(n+3), .. . }. For example, the subcarrier spacing used for PDCCH is Δf_(n+m) ifthe indicated value is m (e.g., m=0, 1, 2, 3, . . . ). As anotherexample, if

${\frac{\Delta f_{n + 1}}{\Delta f_{n}} = 2},$the subcarrier spacing used for PDCCH is 2^(m)×f_(n) if the indicatedvalue is m (e.g., m=0, 1, 2, 3, . . . ). Alternatively, the subset canbe comprised of several subcarrier spacing values around Δf_(n)supported in the system, e.g., {Δf_(n−1), Δf, Δf_(n+1), Δf_(n+2), . . .}.

Option 4:

Conditional indication of whether the subcarrier spacing used for PDCCHis the same as that used by synchronization and PBCH. In this option,there can be a separate field (e.g., 1 bit) to indicate whether thesubcarrier spacing used for PDCCH is the same as that used bysynchronization and PBCH or not. If not the same, it may means that apre-defined different subcarrier spacing is used for PDCCH.Alternatively, if the same, there is no additional indication of thesubcarrier spacing values. If not same, there is additional indicationabout the subcarrier spacing used for PDCCH. The indication method canbe similar as option 1, 2 or 3.

Option 5:

Joint encoding of the numerology indication filed with other field. Inthis option, the numerology indication and other files can be jointlyencoded, e.g., the location of the PDCCH, and so on.

FIG. 14 illustrates a flowchart for obtaining numerology information bya UE according to an embodiment of the present disclosure.

Referring to FIG. 14 , a process of a UE for obtaining numerologyinformation for synchronization, PBCH and PDCCH is illustrated. Inoperation S1410, the UE detects synchronization signals (e.g., PSS/SSS).In operation S1420, the UE obtains the numerology information (e.g.,subcarrier spacing Δf_(i), CP pattern) used for synchronization signals.In operation S1430, the UE decodes PBCH, based on the numerologyinformation used for synchronization signals. In operation S1440, the UEobtains the numerology information used for PDCCH transmission (e.g.,Δf_(j)). In operation S1450, the UE receives PDCCH based on theindicated numerology for PDCCH, i.e., Δf_(j).

FIG. 15 illustrates a flowchart for obtaining numerology informationused for PDCCH by a UE according to embodiments of the presentdisclosure.

Referring to FIG. 15 illustrations of operation S1440 shown in FIG. 14 ,respectively for Option 1, 2 and 3 are provided.

In option 1, the UE obtains the indication X of numerology informationused for PDCCH. The UE obtains the numerology Δf_(j) corresponding toindication X, among the candidates in the full numerology set. In option2, the UE obtains the indication X of numerology information used forPDCCH. The UE obtains the numerology Δf_(j) which matches withindication X, among the candidates in the pre-defined numerology subsetincluding Δf_(i). In option 3, the UE obtains the indication X ofnumerology information used for PDCCH. The UE obtains the numerologyΔf_(j) based on a pre-defined relationship or function Δf_(j)=f(Δf_(i),X).

5) Physical Downlink Control Channel (PDCCH) Location and SizeIndication

In LTE, the synchronization signals and PBCH are mapped to the centralresources (i.e., 6 PRBs) around the carrier center frequency in asymmetric manner, i.e., the center of synchronization signals and PBCHis always aligned with the carrier center frequency. In the futurecellular networks, there may be the case that the synchronizationsignals and PBCH are mapped in a certain portion of the resources ratherthan the central resources around the carrier center frequency. For thePDCCH, it is possible that the PDCCH can be mapped to the centralresources around the carrier center frequency, or in a certain portionof the resources rather than the central resources around the carriercenter frequency.

It may be assumed that the synchronization signals and PBCH aretransmitted in the same frequency location, the offset between thecenter frequency of synchronization signals and the carrier centerfrequency can be indicated in the MIB. Together with the systembandwidth information, the frequency resources occupied by the carriercan be obtained. The frequency offset or difference between the centerfrequency of synchronization signals and the carrier center frequencycan be indicated in the MIB or SIB.

FIG. 16 illustrates an example for indicating location and size of thePDCCH according to an embodiment of the present disclosure.

Referring to FIG. 16 , an example is illustrated to show that thecarrier center frequency can be derived based on the indication in MIB.The following indication methods can be considered:

Option 1:

The frequency offset between the center frequency of synchronizationsignals and the carrier center frequency can be indicated by integertimes of a pre-defined value f_(offset-unit).

The pre-defined value (f_(offset-unit)) can be the minimum offsetbetween two candidate locations in the frequency domain. For example,the pre-defined value can be the same as the size of synchronizationraster of UE (f_(sync-raster)). The size of synchronization raster of UE(f_(sync-raster)) can be different in different frequency bands.Alternatively, the f_(offset-unit) can be the same as the RB size in thecarrier (f_(RB)), or the lowest common multiple of the size ofsynchronization raster and RB size f_(lcn-raster-RB)). The RB size maydepend on the subcarrier spacing used in the carrier, e.g., 180 kHzassuming subcarrier spacing of 15 kHz and 12 subcarriers per RB, or 360kHz assuming subcarrier spacing of 30 kHz and 12 subcarriers per RB. Ifthe size of synchronization raster is 100 kHz, the lowest commonmultiple of the size of synchronization raster and size of RB is 900 kHzand 1800 kHz, respectively for the case with subcarrier spacing of 15kHz and 30 kHz. Similarly, the size of synchronization raster may dependon the frequency bands, e.g., small size for low frequency bands, andlarge size for high frequency band. Based on a pre-defined rule, theoffset size f_(offset-unit) can be different in different frequencybands, and in different subcarrier spacing cases.

In MIB, the frequency offset between the center frequency ofsynchronization signals and the carrier center frequency can beindicated in terms of number of pre-defined value f_(offset-unit). Forexample, ┌log₂2N┐ bits can be used to indicate the value among n∈[−N,−N+1, . . . , −2, −1, 0, 1, 2, . . . , N−1].

The UE may assume there is an offset with amount of n×f_(offset-unit).The number of required bits may depend on the number of possiblecandidates for synchronization transmission in the system, affected bythe system bandwidth, numerology used for synchronization transmission,and so on. The size of this field can be the same for all cases, or canbe different based on a pre-defined rule.

Option 2:

In MIB, it can be indicated whether the current center frequencydetected by the synchronization signals and PBCH is the carrier centerfrequency or not, e.g., by using 1 bit filed to indicate this. If thesame, there is no need of further indication of the frequency offset.Otherwise, i.e., the currently detected center frequency is not thecarrier center frequency, the following filed may indicate the frequencyoffset, as described in Option 1.

Option 3:

Joint encoding of the frequency offset filed with other field. In thisoption, the frequency offset and other files can be jointly encoded,e.g., the BW, the PDCCH numerology, the location of the PDCCH, and soon.

The PDCCH transmission can be flexible in terms of transmission BW,location in the system BW, and so on. Different from LTE, the PDCCHtransmission BW can be different from the full BW supported in thesystem or carrier. If the PDCCH transmission BW is less than the fullsystem BW, UE needs to know the location of the PDCCH transmission. Orat least, if there are multiple PDCCH regions, the location indicationcan be applicable to a pre-defined common control sub-band. Here thelocation may mean a reference frequency location for PDCCH resourcemapping, or a reference frequency location to search PDCCH resourcemapping unit. For example, the center of a control sub-band can be areference frequency location for PDCCH location indication.

FIG. 17 illustrates an example for indicating location and size of thePDCCH according to another embodiment of the present disclosure.

Referring to FIG. 17 , it is assumed that the PDCCH may mean a referencecontrol sub-band, e.g., a common control sub-band, but not limitedthereto. There is case that the PDCCH may not always be mapped aroundthe carrier center frequency. Since the center frequency ofsynchronization signals and the carrier center frequency may bedifferent, it is possible that the PDCCH may be mapped around the centerfrequency detected by PSS/SSS/PBCH, as shown in FIG. 17 . It can beindicated whether the PDCCH is mapped based on the carrier centerfrequency or the current center frequency detected by PSS/SSS/PBCH,e.g., by 1 bit. Alternatively, it can be indicated whether the PDCCH ismapped based on the current center frequency detected by PSS/SSS/PBCH ornot, e.g., by 1 bit. This indication can be jointly encoded with anotherfield, e.g., indication of difference between the center frequency ofsynchronization signals and the carrier center frequency. In this case,a combined indication field can be used to indicate the differencebetween the center frequency of synchronization signals and the carriercenter frequency, and the PDCCH location. For example, 2 bits can beused to indicate the following cases:

Case 1: The center frequency of synchronization signals is the same asthe carrier center frequency, and the PDCCH location is in the carriercenter frequency, as shown in the example of FIG. 1B

Case 2: The center frequency of synchronization signals is differentfrom the carrier center frequency, and the PDCCH location is in thecenter frequency of synchronization signals, as shown in the example ofFIG. 5B

Case 3: The center frequency of synchronization signals is differentfrom the carrier center frequency, and the PDCCH location is in thecarrier center frequency, as shown in the example of FIG. 5A

Case 4: Reserved.

Depending on the indication cases, there is possible pending furtherindication of the difference between the center frequency ofsynchronization signals and the carrier center frequency, e.g., in Case2 and 3. Otherwise, there can be no further indications since the centerfrequency of synchronization signals is the same as the carrier centerfrequency.

Referring to FIG. 16 or FIG. 17 , assuming that the PDCCH is mappedaround a certain reference frequency location, the PDCCH transmission BWis needed for PDCCH decoding. It is also possible that the indicatedPDCCH size is only for the common control subband. It can bepre-defined, derived implicitly, or signaled to the UEs in MIB or SIB.The following methods can be considered:

Option 1:

Pre-defined size without indication. Different sizes can be consideredfor different system BW cases or in different frequency bands. Forexample, the size can be X when the system BW is less than BW_i, and Ywhen the system BW is larger than BW_i but less than BW_j, and Z whenthe system BW is larger than BW_j. The values of X, Y, Z and BW_i, BW_jcan be pre-defined.

Option 2:

The PDCCH transmission BW can be explicitly indicated. The BW optionsfor PDCCH transmission can be pre-defined. For example, the BW optionsfor PDCCH transmission can be selected from the supported system BWcases and/or the supported UE BW case. The BW option for PDCCHtransmission is explicitly indicated.

Option 3:

To reduce the overhead, the BW options for PDCCH transmission case canbe pre-defined for all the system BW cases. For example, the BW optionsfor PDCCH transmission can be selected from the supported system BWcases and/or the supported UE BW case. Given a system BW, the BW optionfor PDCCH transmission is indicated. The required number of indicationcan be different for different BW cases and numerology cases.

Option 4:

There can be one bit indication to inform that if the current PDCCHtransmission BW is the same as the system BW. If the same, there is nofurther signaling. If not, it is further indicated about the actual usedPDCCH transmission BW. The indication method can be the same as Option 1or 2 or 3.

Option 5:

The PDCCH transmission BW can be related to the BW of thesynchronization signals and PBCH. Assuming that BW of thesynchronization signals and PBCH is X, the indication can be afunctionality of the BW X, e.g., X, 2X, and so on. The functionality canbe different for different cases, e.g., in terms of system BW, and/orfrequency band, and so on.

If there is no restriction to always map the PDCCH location around thecarrier center frequency or the center frequency detected based onPSS/SSS/PBCH, the PDCCH transmission can be located in the system BW ina more flexible manner. The PDCCH location information needs to beadditionally signaled. The following PDCCH location information can besignaled.

Option 1:

The reference PRB index used by PDCCH transmission is indicated. Therequired number of indication can be different for different BW casesand numerology cases.

Option 2:

To reduce the overhead, a predefined number of candidate reference PRBsfor PDCCH transmission can be defined. It is indicated which referencePRB case is used in the current PDCCH transmission.

Option 3:

The offset cases between the center of PDCCH transmission and apre-defined reference frequency can be signaled. The pre-definedreference frequency can be the carrier center frequency, or the centerfrequency of the PSS/SSS/PBCH transmission.

Besides the PDCCH location in the frequency domain, it may be alsonecessary to indicate the PDCCH location in the time domain in somescenarios. In LTE, the NR PDCCH is always located in the first one ormore OFDM symbols in a subframe. The UEs can by default searchPCFICH/PHICH/PDCCH from the 1^(st) OFDM symbol. However, in the NRsystem, various situations and flexible design need to be considered.

FIG. 18 illustrates an example for LTE-NR coexistence in the samespectrum respectively for FDD and TDD modes according to an embodimentof the present disclosure.

Referring to FIG. 18 , it is possible that NR may coexist with LTEspectrum, i.e., existed with LTE. For example, in the LTE FDD mode, NRcan utilize the LTE MBSFN subframes in the downlink case, and utilizethe normal subframe in the uplink case. In the LTE TDD mode, NR canutilize the LTE MBSFN subframes and uplink subframes. An example ofLTE-NR coexistence in the same spectrum is shown in FIG. 18 ,respectively for FDD and TDD modes.

FIG. 19 illustrates an example for a subframe boundary aligned betweenNR and LTE according to an embodiment of the present disclosure.

In FDD case, the NR system can operate in the LTE MBSFN subframes. It isassumed that the LTE and NR are synchronized in the subframe level,i.e., the subframe boundary is aligned between NR and LTE, as shown inFIG. 19 . However, in the LTE MBSFN subframe, the first or two OFDMsymbols need to be reserved for normal LTE usage, e.g., CRStransmission, LTE PCFICH/PHICH/PDCCH transmission, etc.

FIG. 20 illustrates an example for first two OFDM symbols reserved in aMBSFN subframe according to an embodiment of the present disclosure.

Referring to FIG. 20 , the first two OFDM symbols are reserved in aMBSFN subframe. Therefore, when the LTE MBSHN subframes are used by NR,the first one or multiple OFDM symbols need to be reserved for LTE usagewhile not available for NR.

FIG. 21 illustrates an example for subcarrier spacing used in NRaccording to an embodiment of the present disclosure.

Referring to FIG. 21 , when 15 kHz subcarrier spacing is used in NR,i.e., the same as LTE numerology, up to two OFDM symbols may not be usedin a NR subframe. When 30 kHz subcarrier spacing is used in NR, up tofour OFDM symbols may not be used in a NR subframe.

When NR UEs try to access the system, it detects the synchronizationsignals and read PBCH. Then the UEs try to get the full systeminformation for system access. The system information may be scheduledby PDCCH. Similar as LTE, the NR PDCCH can be located in the first oneor more OFDM symbols in a subframe. However, in the NR-LTE coexistencescenario, the situation that the first one or more OFDM symbols are notavailable in a subframe needs to be handled.

It is possible to indicate UEs about the starting point to monitor thePDCCH; at least the indication can be applied to the subframes where UEstry to read some essential system information, e.g., SIB 1. Theindication can be carried in MIB (PBCH). The following options can beconsidered to indicate the offset to monitor PDCCH in a certain subframe(e.g., for system information reception):

Option 1: There can be 1 bit indication to inform UEs, if the PDCCHstarts from the 1^(st) OFDM symbol in a subframe or slot. If not, the UEmay need to monitor PDCCH in a blind manner. For example, the UE may tryfrom the 2^(nd) OFDM symbol, and then the 3^(rd) OFDM symbol for PDCCHsearching.

Option 2: There can be 1 bit indication to inform UEs, if the PDCCHstarts from the 1^(st) OFDM symbol or a pre-defined OFDM symbol index ina subframe or slot. The pre-defined OFDM symbol index may be determinedby the worst case in LTE-NR coexistence case, e.g., 2 OFDM symbols inLTE. Then for NR operation, the pre-defined OFDM symbol index can be 3for 15 kHz subcarrier spacing case, 5 for 30 kHz subcarrier spacingcase, and so on. The pre-defined OFDM symbol index can be different fordifferent numerology cases.

Option 3: There can be an indication field to explicitly indicate thestarting OFDM symbol index in a subframe or slot. For example, with 2bit indication, 4 predefined candidate starting OFDM symbol index can beindicated, e.g., 1, 2, 3, 4. Similarly, the candidate starting OFDMsymbol index can be different for different numerologies. For example,in case of 15 kHz subcarrier spacing case, {1, 2, 3, reserved} can beindicated, and in case of 30 kHz subcarrier spacing case, {1, 2, 3, 5}are indicated.

FIG. 22 illustrates a flowchart for obtaining PDCCH location and sizeinformation by a UE according to an embodiment of the presentdisclosure.

Referring to FIG. 22 , a process of a UE obtaining PDCCH location andsize information is illustrated. The UE detects synchronization signals(e.g., PSS/SSS) in operation S2210. The UE obtains the numerologyinformation (e.g., subcarrier spacing, CP pattern) used forsynchronization signals in operation S2220. The UE decodes PBCH, basedon the numerology information used for synchronization signals inoperation S2230. The UE obtains the numerology information, and locationinformation used for PDCCH transmission in operation S2240. The UEreceives PDCCH based on the derived numerology/location/size informationfor PDCCH in operation S2250.

6) Common Control Channel

It is necessary to transmit some control information which is common inthe cell. The control information may be related to the essentialinformation of the resource utilization, e.g., the size of PDCCH in thetime and frequency domain, the resource availability in the current TTI.In addition, similar as in LTE, the scheduling information of systeminformation, paging, and random access response (RAR) may be transmittedin the common control channel.

In LTE, a Physical Control Format Indicator Channel (PCFICH) is used toindicate the number of OFDM symbols used by the control channel in eachsubframe. In the next generation cellular networks, it is also possibleto have a dedicated channel like PCFICH to indicate the number of OFDMsymbols used by the control channel. Or, the number of OFDM symbols canbe pre-defined, which may be different in different system BW case. Forexample, for small system BW case, 2 or 3 OFDM symbols are used forcontrol channel transmission in a TTI. For larger system BW case, 1 or 2symbols can be used. According to the resource availability in differentsystem BW, the pre-defined number of OFDM symbols can be used forcontrol channel transmission in each system BW case, which avoids theneed of indication in each TTI. Alternatively, it is possible to haveindication in some cases, and pre-defined number of OFDM symbols in someother cases. If indicated, the indication can be applicable to thecommon control sub-band only, or applicable to all the controlsub-bands.

It is also possible to indicate the used control channel resources inthe frequency domain. For example, if there are multiple controlsub-bands in the frequency, it is possible to indicate the number ofused control sub-bands, or a bitmap of the used control sub-bands in thecurrent TTI.

FIG. 23 illustrates an example for a common control channel according toan embodiment of the present disclosure.

Referring to FIG. 23 , the common control channel can be the defaultcontrol region for UE to access before connected to the network. It isalso possible to be the default control region for UE in idle mode tomonitor downlink control information (DCIs). In that case, the frequencydomain resource allocations indicated in the DCI may only apply to thesame bandwidth as the common control channel for data transmission, asshown in FIG. 23 . This enables a UE to keep the same RF bandwidth forboth control and data channels. By restricting the UE RF bandwidth inthe pre-configured smaller bandwidth, it is helpful to reduce the UEpower consumptions compared to receiving the whole system bandwidth.

7) Control Subband

After the UE accesses the common control channel, and obtains thenecessary system information and configurations for initial access, theUE can perform random access to the network. During the random accessprocedure, the gNB can configure a certain control subband to UE for DCImonitoring in the connected mode. The complete information of controlsubband configurations can be included in the system information,including the number of control subbands, location the in frequencydomain, and size (e.g., in terms of RBs), and used numerology (e.g.,subcarrier spacing). The control subband can occupy a contiguous numberof RBs in the frequency domain, or non-contiguous number of RBs.

FIG. 24 illustrates an example for a control subband according to anembodiment of the present disclosure.

Referring to FIG. 24 , one subband can occupy a portion in the systembandwidth. The control subband may occupy a bandwidth portion differentfrom the common control channel, as shown in Case 1. Alternatively, thecommon control channel may be included in the control subband, as shownin Case 2.

FIG. 25 illustrates an example for keeping the same RF bandwidth forboth control and data channels according to an embodiment of the presentdisclosure.

According to different configurations of the control subbands, the UE'sbehavior may be different. Basically, the UE in default monitors theconfigured control subband based on the configured monitoring interval.

Referring to FIG. 25 , UE-1 and UE-2 are configured to monitor differentcontrol subband with different monitoring intervals. Similarly, thefrequency domain resource allocations indicated in the DCI may onlyapply to the same bandwidth as the control subband for datatransmission, as shown in FIG. 25 . This enables UE to keep the same RFbandwidth for both control and data channels. By restricting the UE RFbandwidth in the configured subband, it is helpful to reduce the UEpower consumption compared to receiving the whole system bandwidth.

In Case 1 of FIG. 24 , if the UE does not receive common controlchannel, some necessary control information may be transmitted in thecontrol subband. For example, the number of OFDM symbols used for thecontrol subband can be indicated, which means there can besubband-specific PCFICH. In addition, there is necessity to receiveindication of system information modification, which can be indicated inthe paging information transmitted in the common control channel.Therefore, the system information modification indication can beindicated in the control subband. After receiving indication of systeminformation modification, the UE needs to receive both common controlchannel and configured control subband. The motivation of receiving thecommon control channel is to receive the updated system information.After finishing system information update, the UE can switch to receivethe configured control subband only.

FIG. 26 illustrates a flowchart for indicating if there is any activeDCI transmission in the current control subband according to anembodiment of the present disclosure.

In order to avoid PDCCH blind decoding attempts and reduce UE powerconsumptions, it is possible to have a pre-indication in a controlsubband to indicate if there is any active DCI transmission in thecurrent control subband. The pre-indication can be a 1-bit YES/NOindication to inform UE if there is a need to continue trying PDCCHblind decoding attempts in the control subband. The location to transmitthis indication within a certain control subband can be pre-defined.

Referring to FIG. 26 , the UE behavior with the above operation case isillustrated. The UE receives the signals in the control subband inoperation S2610. The UE extracts and decodes the indication field inoperation S2620. The UE identifies whether it is indicated that thereare active DCI transmissions in operation S2630. If it is indicated thatthere are active DCI transmissions, the UE tries blind decoding based onthe candidate DCI locations in operation S2640. If it is not indicatedthat there are active DCI transmissions, the UE skip any blind decodingin operation S2650.

FIG. 27 illustrates a flowchart for indicating the aggregation levels ofDCIs transmitted in the current TTI according to an embodiment of thepresent disclosure.

To reduce the number of PDCCH blind decoding attempts, it is possible toindicate the aggregation levels (e.g., 1, 2, 4, 8) of DCIs transmittedin the current TTI. A bitmap can be transmitted to indicate if a certainaggregation level is used or not for the DCIs transmitted in the currentTTI. The location to transmit this indication can be pre-defined withinthe common control channel or a certain control subband. If transmittedin the common control channel, the indication may apply to theUE-specific DCIs in the whole system bandwidth of the current TTI. Iftransmitted in the control subband, the indication may only apply to theUE-specific DCIs in that control subband. For example, a 4-bit bitmapcan indicate if the aggregation level 1, 2, 4, 8 is used or not. Basedon this indication, the UEs can only try the blind decoding of DCIs withthe indicated aggregation levels, while ignore the blind decoding ofDCIs with non-indicated aggregation levels.

Referring to FIG. 27 , the UE behavior with the above operation case isillustrated. The UE receives the signals in the control region inoperation S2710. The UE extracts and decodes the indication field inoperation S2720. The UE checks the indicated DCI aggregation levels usedin the current TTI in operation S2730. If there is an indicated DCIaggregation level in operation S2740, the UE tries blind decoding basedon indicated DCI aggregation levels, and skips the ones not indicated inoperation S2750. If there is not an indicated DCI aggregation level, theUE skips any blind decoding in operation S2760.

FIG. 28 illustrates a flowchart for indicating UE groups scheduled inthe current TTI according to an embodiment of the present disclosure.

Alternatively, it is possible to indicate some partial information ofscheduled UE in the current TTI. For example, there can be indication ofpartial information of the UE RNTIs scheduled in the current TTI. TheUEs can be divided into several groups based on a pre-defined rule,e.g., X groups. An X-bit bitmap can indicate if a certain UE group hasscheduled UEs in the current TTI. For example, if X=10, there can be 10different UE groups which have different last digit in the UE RNTI. Thelocation to transmit this indication can be pre-defined within thecommon control channel or a certain control subband. If transmitted inthe common control channel, the indication may apply to the UE-specificDCIs in the whole system bandwidth of the current TTI. If transmitted inthe control subband, the indication may only apply to the UE-specificDCIs in that control subband.

Referring to FIG. 28 , the UE behavior with the above operation case isillustrated. The UE receives the signals in the control region inoperation S2810. The UE extracts and decodes the indication field inoperation S2820. The UE checks the indicated UE groups scheduled in thecurrent TTI in operation S2830. If the UE related group is indicated inoperation S2840, the UE tries blind decoding based on the candidate DCIlocations in operation S2850. If the UE related group is not indicated,the UE skips any blind decoding in operation S2850.

8) Control Unit Mapping Method

The mapping of PDCCHs to resource elements can be based on a structureof control unit (CU), which in essence is a set of a pre-defined numberof resource elements. One or more CUs can be used to transmit a singlePDCCH. For example, a PDCCH may be transmitted by one, two, four, oreight CUs, which is known as aggregation level. The required number ofCUs for a certain PDCCH depends on the payload size of the controlinformation (DCI payload) and the channel-coding rate. This is used torealize link adaptation for the PDCCH; if the channel conditions for theterminal to which the PDCCH is intended are disadvantageous, a largernumber of CUs needs to be used compared to the case of advantageouschannel conditions. The number of CUs used for a PDCCH is also referredto as the aggregation level. The number of CUs available for PDCCHsdepends on the size of the control region, e.g., PDCCH transmission BWand number of OFDM symbols, and the number of resources occupied byother signals/channels in the control region.

FIG. 29 illustrates that CUs available for PDCCH transmission arenumbered from zero and upward according to an embodiment of the presentdisclosure.

Referring to FIG. 29 , the CUs available for PDCCH transmission can benumbered from zero and upward. A specific PDCCH can thus be identifiedby the numbers of the corresponding CUs.

FIG. 30 illustrates an aggregation of control channel elements (CCEs)according to an embodiment of the present disclosure.

Referring to FIG. 30 , in case of PDCCH using aggregated CUs, to reducethe complexity, certain restrictions on the aggregation of contiguousCUs have been specified. For example, an aggregation of eight CCEs canonly start on CCE numbers evenly divisible by 8, as illustrated in FIG.8B. The same principle is applied to the other aggregation levels.

The PDCCH transmission needs to consider the possibility that there areUEs with minimum supported bandwidth, e.g., BW₀. Therefore, thecell-specific common control information needs to be transmitted byPDCCH within the bandwidth BW₀, which can be the common control subbanddescribed before. This guarantees that all UEs can receive the commoncontrol information, e.g., the scheduling information of the systeminformation transmission. The response to UEs' random access can also betransmitted by PDCCH within the bandwidth BW₀, since the gNB may have noinformation about the UE BW when receiving a random access request.

After UEs successfully access the system, the UEs may inform the UEcapability (including the UE BW information) to the gNB. The gNB hasinformation of BW information of all connected UEs. Based on the trafficand capability of accessed UEs, the gNB may decide the bandwidth usedfor PDCCH transmission. The gNB may indicate the supported BW cases forPDCCH transmission and reception. This can be signaled in the MIB or SIBas cell-specific information. For a UE with bandwidth BW_(i), the gNBmay signal a supported control subband case for UE to monitor PDCCH, asUE-specific information. The signaled control subband case for PDCCHmonitoring to UE can be equal to or less than the UE BW, to allow beable to monitor the PDCCH transmission.

FIG. 31 illustrates that CUs used for PDCCH transmission are locatedwithin the control subband according to an embodiment of the presentdisclosure.

To transmit PDCCH to the UEs with different control subband, it shouldbe ensured that the CUs used for PDCCH transmission is located withinthe control subband.

Referring to FIG. 31 , there are a total of NM CUs within the system BW,and N_(i) CUs within a given bandwidth BW_(i). The UE which has abandwidth during the range (BW_(i), BW_(i+1)) can be configured toreceive the PDCCH within a bandwidth BW_(i).

Due to the special feature above, the CU mapping needs to be designed inan efficient manner. As discussed above, a CU is composed of apre-defined number of resource element groups (REGs). The REG may becomprised of a fixed number of useful REs based on a pre-defined rule,or can be one ore multiple PRBs. The following methods can be consideredto construct a CU:

Option 1:

A CU is constructed by K consecutive REGs in one OFDM symbol. Option 1a:The CUs can be constructed from one side of the PDCCH transmission BW.In an OFDM symbol, the first K consecutive REGs from the lower frequencyside of the PDCCH transmission BW become one CU, and the next Kconsecutive REGs become another CU, and so on.

Option 1b: The CUs can be constructed from the centre of the PDCCHtransmission BW. In an OFDM symbol, from the centre to the higherfrequency side of the PDCCH transmission BW, every K consecutive REGsbecome one CU. Similarly, from the centre to the lower frequency side ofthe PDCCH transmission BW, every K consecutive REGs become one CU.

Option 1c: In an OFDM symbol, around the centre frequency of the PDCCHtransmission BW, one CU is composed of the surrounding closest K REGs,e.g., K/2 REGs from the higher frequency side and K/2 REGs from thelower frequency side. Similarly, the next CU is composed of the nextavailable closest K REGs, half from the higher frequency side andanother half from the lower frequency side, and so on.

Option 2:

A CU is constructed by K REGs from all OFDM symbols in the controlregion.

Option 2a: The CUs can be constructed from one side of the PDCCHtransmission BW. From the lower frequency side of the PDCCH transmissionBW, a CU collects the first K consecutive REGs in the order of firstlowest subcarrier index, and then lowest symbol index, and so does theremaining CUs.

Option 2b: The CUs can be constructed from the center of the PDCCHtransmission BW. From the center to the higher frequency side of thePDCCH transmission BW, a CU collects the first K consecutive REGs in theorder of first lowest subcarrier index, and then lowest symbol index,and so does the remaining CUs. From the center to the lower frequencyside of the PDCCH transmission BW, a CU collects the first K consecutiveREGs in the order of first highest subcarrier index, and then highestsymbol index, and so does the remaining CUs.

Option 2c: The CUs can be constructed around the centre of the PDCCHtransmission BW. From the centre frequency of the PDCCH transmission BW,a CU collects the first K REGs in the order of first the closestsubcarrier index, and then lowest symbol index, and so does theremaining CUs.

FIG. 32 illustrates that the REGs are indexed in the order of closestsubcarrier index first, and then lowest symbol index according to anembodiment of the present disclosure.

Referring to FIG. 32 , where the REGs are indexed in the order of firstthe closest subcarrier index, and then lowest symbol index. A first CUcan then composed by the REGs from index 0 to K−1, and the next CU iscomposed by the resource element groups from index K to 2*K−1, and soon.

FIG. 33 illustrates a structure of a UE according to an embodiment ofthe present disclosure.

Referring to FIG. 33 , the UE may include a transceiver ortransmission/reception unit 3310, a controller or processor 3320, and astorage unit 3330. In the present disclosure, the controller 3320 may bedefined as a circuit or an application specific integrated circuit or atleast one processor.

The transceiver 3310 may transmit and receive signals with other networkentities. The transceiver 3310 may receive system information from, forexample, a base station and may receive a synchronization signal or areference signal.

The controller 3320 may control the overall operation of the UEaccording to the embodiment of the present disclosure. For example, thecontroller 3320 may control the signal flow between each block toperform the operation according to the flowcharts described above. Indetail, controller 3320 may control operations proposed by the presentdisclosure.

The controller 3320 is coupled with the transceiver 3310 and thecontroller 3320 is configured to detect synchronization signals, obtainfirst numerology information for the synchronization signals, decode aphysical broadcast channel (PBCH) based on the first numerologyinformation, obtain second numerology information for a physicaldownlink control channel (PDCCH) according to a result of the decoding,and receive control information on the PDCCH based on the secondnumerology information.

The second numerology information indicates a subcarrier spacing for thePDCCH within a subcarrier spacing set. The subcarrier spacing set is forlower frequency bands or higher frequency bands, the lower frequencybands are below reference frequency band and the higher frequency bandsare above the reference frequency band.

According to an embodiment, the controller 3320 is configured to obtainfirst information on bandwidth for PDCCH transmission according to aresult of the decoding.

According to another embodiment, the controller 3320 is configured toobtain second information according to a result of the decoding, thesecond information including at least one of a candidate PRB for PDCCHtransmission and offset between a center of the PDCCH transmission and areference frequency.

According to the other embodiment, the controller 3320 is configured toobtain third information on a start symbol index to monitor the PDCCHaccording to a result of the decoding.

The storage unit 3330 may store at least one of information transmittedand received through the transceiver 3310 and information generatedthrough the controller 3320.

FIG. 34 illustrates a structure of a base station according to anembodiment of the present disclosure.

Referring to FIG. 34 , a base station (or gNB) may include a transceiveror transmission/reception unit 3410, a controller or processor 3420, anda storage unit 3430. In the present disclosure, the controller 3420 maybe defined as a circuit or an application specific integrated circuit orat least one processor.

The transceiver 3410 may transmit and receive signals with other networkentities. The transceiver 3410 may transmit system information to theUE, for example, and may transmit a synchronization signal or areference signal.

The controller 3420 may control the overall operation of the basestation according to the embodiment of the present disclosure. Forexample, the controller 3420 may control the signal flow between eachblock to perform the operation according to the flowcharts describedabove. In particular, the controller 3420 may control operationsproposed by the present disclosure to support flexible UE bandwidth.

The controller 3420 is coupled with the transceiver 3410 and isconfigured to transmit, to user equipment (UE), synchronization signalsand first numerology information for the synchronization signals,generate second numerology information for a physical downlink controlchannel (PDCCH), transmit, to the UE, the second numerology informationon a physical broadcast channel (PBCH) based on the first numerologyinformation, and transmit, to the UE, control information on the PDCCHbased on the second numerology information.

The second numerology information indicates a subcarrier spacing for thePDCCH within a subcarrier spacing set. The subcarrier spacing set is forlower frequency bands or higher frequency bands, the lower frequencybands are below reference frequency band and the higher frequency bandsare above the reference frequency band.

According to an embodiment, the controller 3420 is configured togenerate at least one of first information on bandwidth for PDCCHtransmission, second information including at least one of a candidatePRB for PDCCH transmission and offset between a center of the PDCCHtransmission and a reference frequency, and third information on a startsymbol index to monitor the PDCCH.

The storage unit 3430 may store at least one of informationtransmitted/received through the transceiver 3410 and informationgenerated through the controller 3420.

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a terminal in a wirelesscommunication system, the method comprising: receiving, from a basestation, a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS) based on a first subcarrier spacing;receiving, from the base station, a master information block (MIB) on afrequency band, based on the first subcarrier spacing, wherein the MIBincludes first information on a second subcarrier spacing for physicaldownlink control channel (PDCCH) and second information on a firstsymbol index in a slot for monitoring the PDCCH; identifying, based onthe first information included in the MIB, the second subcarrier spacingfor the PDCCH from one of a first subcarrier spacing set or a secondsubcarrier spacing set corresponding to the frequency band on which theMIB is received; and receiving, from the base station, the PDCCH basedon the second subcarrier spacing.
 2. The method of claim 1, wherein thefirst subcarrier spacing set corresponds to a lower frequency band andthe second subcarrier spacing set corresponds to a higher frequencyband.
 3. The method of claim 1, wherein the first information includedin the MIB includes an indication bit corresponding to the secondsubcarrier spacing for the PDCCH.
 4. The method of claim 1, furthercomprising: receiving, from the base station, a system information block(SIB) scheduled by the PDCCH based on the second subcarrier spacing. 5.A method performed by a base station in a wireless communication system,the method comprising: transmitting, to a terminal, a primarysynchronization signal (PSS) and a secondary synchronization signal(SSS) based on a first subcarrier spacing; transmitting, to theterminal, a master information block (MIB) on a frequency band, based onthe first subcarrier spacing, wherein the MIB includes first informationon a second subcarrier spacing for physical downlink control channel(PDCCH) and second information on a first symbol index in a slot for thePDCCH; and transmitting, to the terminal, the PDCCH based on the secondsubcarrier spacing, wherein the second subcarrier spacing is indicatedby the first information included in the MIB from one of a firstsubcarrier spacing set or a second subcarrier spacing set correspondingto the frequency band on which the MIB is transmitted.
 6. The method ofclaim 5, wherein the first subcarrier spacing set corresponds to a lowerfrequency band and the second subcarrier spacing set corresponds to ahigher frequency band.
 7. The method of claim 5, wherein the firstinformation included in the MIB includes an indication bit correspondingto the second subcarrier spacing for the PDCCH.
 8. The method of claim5, further comprising: transmitting, to the terminal, a systeminformation block (SIB) scheduled by the PDCCH based on the secondsubcarrier spacing.
 9. A terminal in a wireless communication system,the terminal comprising: a transceiver configured to transmit andreceive a signal; and a controller configured to: receive, from a basestation, a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS) based on a first subcarrier spacing,receive, from the base station, a master information block (MIB) on afrequency band, based on the first subcarrier spacing, wherein the MIBincludes first information on a second subcarrier spacing for a physicaldownlink control channel (PDCCH) and second information on a firstsymbol index in a slot for the PDCCH, identify, based on the firstinformation included in the MIB, the second subcarrier spacing for thePDCCH from one of a first subcarrier spacing set or a second subcarrierspacing set corresponding to the frequency band on which the MIB isreceived, and receive, from the base station, the PDCCH based on thesecond subcarrier spacing.
 10. The terminal of claim 9, wherein thefirst subcarrier spacing set corresponds to a lower frequency band andthe second subcarrier spacing set corresponds to a higher frequencyband.
 11. The terminal of claim 9, wherein the first informationincluded in the MIB includes an indication bit corresponding to thesecond subcarrier spacing for the PDCCH.
 12. The terminal of claim 10,wherein the controller is further configured to receive, from the basestation, a system information block (SIB) scheduled by the PDCCH basedon the second subcarrier spacing.
 13. A base station in a wirelesscommunication system, the base station comprising: a transceiverconfigured to transmit and receive a signal; and a controller configuredto: transmit, to a terminal, a primary synchronization signal (PSS) anda secondary synchronization signal (SSS) based on a first subcarrierspacing, transmit, to the terminal, a master information block (MIB) ona frequency band, based on the first subcarrier spacing, wherein the MIBincludes first information on a second subcarrier spacing for a physicaldownlink control channel (PDCCH) and second information on a firstsymbol index in a slot for monitoring the PDCCH, and transmit, to theterminal, the PDCCH based on the second subcarrier spacing, wherein thesecond subcarrier spacing is indicated by the first information includedin the MIB from one of a first subcarrier spacing set or a secondsubcarrier spacing set corresponding to the frequency band on which theMIB is transmitted.
 14. The base station of claim 13, wherein the firstsubcarrier spacing set corresponds to a lower frequency band and thesecond subcarrier spacing set corresponds to a higher frequency band.15. The base station of claim 13, wherein the first information includedin the MIB includes an indication bit corresponding to the secondsubcarrier spacing for the PDCCH.
 16. The base station of claim 13,wherein the controller is further configured to transmit, to theterminal, a system information block (SIB) scheduled by the PDCCH basedon the second subcarrier spacing.